WATER. 343 



Q. How can WATER be converted into a GAS ? 



A. By increasing its latent heat, the 

 particles of water are again subdivided 

 into invisible steam. 



Q. Why is PUMP water called HARD water ? 

 A. Because it is laden with foreign 



matters, and will not readily dissolve 



substances immersed in it. 



Q. What makes pvwp-water HARD ? 



A. Because when it filters through 

 the earth, it becomes impregnated with 

 sulphate of lime, and many other impurities 

 from the earths and minerals with which 

 it comes in contact. 



Q. Why is it difficult to WASH our HANDS 

 clean with HARD water ? 



A. Because the soda of the soap 

 combines with the sulphuric acid of the 

 hard water, and the oil of the soap with 

 the lime, and float in flakes on the top 

 of the water. 



N. B. Sulphate of lime consists of sulphuric acid 

 and lime. 



Q. Why is it difficult to wash in SALT WATER ? 

 A. Because salt water contains mu- 

 riatic acid ; and the soda of soap combines 



